The present invention relates to an operating system that is applied to an emergency pump unit, which is used as a fire pump or a drain pump in vessels, for example, the system enabling a two-cycle spark ignition engine, which is used to operate such an emergency pump unit, to be operated with gas oil.
A typical conventional emergency pump unit that is used as a fire pump or a drain pump in vessels employs a two-cycle spark ignition engine that uses gasoline as fuel. This is because such a two-cycle spark ignition engine is light in weight and small in size in comparison to other types of engine, for example, diesel engines, and it is therefore suitable for a fire pump from the viewpoint of startability and portability The prior art suffers, however, from the problems that vessels must have gasoline always ready on hand, and the prior art is inferior in safety.
If a two-cycle spark ignition engine is designed to use fuel other than gasoline in order to solve the above-described problems, it will become difficult to start the engine. In Japanese Patent Public Disclosure (Laid-Open) No. 60-62649 (1985), for example, kerosene is used as fuel and supplied in such a way that, only when the engine is to be started, kerosene is atomized by use of an ultrasonic atomizer that comprises a vibrating plate, and when the engine is running in a steady state, the kerosene is supplied through a carburetor. In this system, however, since the ultrasonic atomizer comprises a vibrating plate, the flow rate of atomized fuel is low, so that the ultrasonic atomizer can be used only at the time of starting the engine, and it is impossible to use a gas oil that is heavier than kerosene.